Muffler for internal combustion engines



Feb. 23, 1937. A. J. MoNAMAh MUFFLER FOR INTERNAL COMBUSTL 'Filed Jan. 18, 1928 INVENToR. mraae e7 WSA/amara A TTORNE Y.

QSQSQQTN mw\mw\mmw .wlw g Feb. 23, 1937. A. J, MQNAMARA 2,071,351

MUFFLER FOR INTERNAL COMBUSTION ENGINES INVENToR. .rmrafe @Mfg/firmar@ A TTORNE Y.

Patented Feb. 23, 1937 UNITED STATES PATENT OFFICE 2,071,351 MUFFLEB FOB INTERNAL COMBUSTION NGINE 4Claims.

'I'his invention relates to an improvement in mufiiers for quieting and muiliing the exhaust gases from internal combustion engines.

Mufiiers for deadening or muil'iing explosive noise of an internal combustion engine are commonly used, especially on automotive vehicles. Common mumer construction consists of a shell arrangement or an assembly of interiitting cups having a plurality of bailies inside which are ar- 10 ranged to more or less tear up the exhaust gases that pass tortuously through the mufiier before reaching the atmosphere. Much of the time the exhaust gases which reach the muiiler are not fully burned and final burning takes place in the l muilier. It is well known that the use of a muiller creates a back pressure of the exhaust gases upon .the engine, due to the fact that the flow of the exhaust gases is interfered with, thereby reducing the efficiency of the engine.

The present invention aims to provide a muiiier which will reduce to a minimum the back pressure upon an engine, and which is constructed so that a charge or body of exhaust gas which may not be completely burned, is torn up in such a manner as to cause the interior portion of this body of exhaust gas to be brought tothe interior portions of the muiler shell. Accordingly, one or more mufiiing devices are provided within the mufiler arranged, in a way, to obstruct the passage of the exterior layers of a body of discharged gas but which permits the more central layers, or the heart of -the body of gas, to pass on through the devices substantially unobstructed. Where a. plurality of such devices are used they are so arranged to successively remove outside layers of a body of gas until the inside of the body of gas itself may be deilected adjacent the interior walls of the muiiler where its heat is dissipated.

-Other objects and advantages of the invention 40 residing in the combination of the elements, ar-

l rangements of the parts, and in the details of construction, will be evident during the course of the description hereinafter, wherein the terms used a are merely descriptive. It will be apparent that there are numerous ways in which a muilier embodying the present invention may be designed other than those shown herein.

In the gures of the accompanying drawings 50 which form a part of this specification, and

wherein like numerals are employed to designate corresponding and like parts throughout the same.

Figure 1 is a central longitudinal sectional view 55 of a cup muiller embodying a preferred form of the`invention, parts thereof being shown fragmental,

Figure 2 is a transverse sectional view on lines 2-2 of Figure 1,

Figure 3 is a partial central longitudinal sectional view showing a modified arrangement of the baiiles of the muiiier shown in Figure 1,

Figure 4 is a central longitudinal sectional view of a shell type muiller embodying a modiied form of the invention, and,

Figures 5 and 6 are transverse sectional views taken. on corresponding lines of Figure 4.

. The muiiler shown in Fig. 1 consists of a multiplicity of interfitting cup members, which when interfltted together form a muiiler shell, generally referenced i. 'I'hese cups may be clamped together by suitable bolts 2 which extend through the mufller with nuts on either end thereof. The exhaust inlet for the muflier is shown at I, the outlet at 4. End plates 5 and 6 are provided for closing the ends of the muffler shell.

This muffler may be made of several types of cup members as shown in the present form. The cup members 1 are provided with relatively small inwardly extending flanges 8 to give the cups sufilcient rigidity and strength but which permit exhaust gases to pass through. 'Ihese cup members 1 act as spacers for cup members 8 that are provided with relatively deep flanges I0. These inwardly extending annular anges lil are provided with a central opening, into which is fixed a tapering tubular member ii. These members ii are in. the nature of reversed megaphones and have the large end i2, thereof, pointed towards the oncoming gases. Preferably, these conical passageways II are circular in cross section but it is within the invention to make them any other shape in cross section.

Cup member l5, having a plurality of apertures i6 formed in the transverse bottom portion i4 thereof, is disposed immediately to the rear of the last spacer cup 1, and a diifusing cone I1, as shown, 'if desired, may be formed in the bottom portion i4 of cup I5. The rear of the muffier is made up of the similar cup members I8, as shown, and a final cup I9 is used to complete the assembly. The cups I0 have an opening 22, formed centrally in the bottom flanges 20 thereof, through which the re-entrant pipe 23 extends inwardly of the muiiler to provide a chamber 2| in which some of the exhaust gases collect to act as a gas cushion.

It is to be appreciated that muiiiers, in order to be most efficient, must be varied in size, shape, etc., for various engines because a mumer which will operate eciently with one engine will not operate eiliciently with another. In the muiiler shown in Fig. l two megaphone shaped members Il are used. Such a construction has been found 5 to be efficient for certain engines, but with other engines it has been found that three, or even more of the megaphone members il are desirablel in order to obtain most efllcient muiiiing. The use of the diffusing cone I1 is advantagpus in connection with the megaphone shaped communicating members Il, but in some instances this diffusing cone can be dispensed with. Also A the provision of a gas cushion chamber at the rear end of the muiiier can, if desired, be dispensed with inasmuch as the present invention is centered around the use of the megaphone shaped passageways Il, with the transverse perforated baffle plate I4, and with, or without, either or both, the diffusing cone i1 and/or the inwardly extending pipe 23.

A modified arrangement of the interior baille members is shown in Figure 3 wherein a transverse perforated baille Ma having a .diffusing cone Ila is disposed between the megaphone shaped passageways Ila. It will be understood that the number of megaphone members can be varied to meet various requirements, and also if it be found desirable, the number of the transverse perforated baille plates Ila, may be varied.

Considering the manner in which the exhaust gases pass through a muiiler, it will be understood that the gases upon leaving the engine have a very high velocity and that they travel through the muiiler at a high rate of speed and often upon enteringthe muiiler are not completely burned. Picture a charge or body of exhaust gas entering the muilier shown in Figure 1 through the' inlet 3. The exhaust gases enter the fairly large front chamber 25 wherein the same may expand, then v40 this charge, cr ,rather a portion thereof, passes on through the tapering tube member Il At this point the outer layers of gas come into contact with the gradually reducing walls of the megaphone member II so that-the movement of the outer layers of the body of gas are interfered with and retarded, whereas, the central part or heart of the charge passes through the opening in the communicating member Ii. Thus the outer layers of gas are broken away or scraped on the central layers.

'Ihe central parts of the charge of gas then pass into the chamber 26, and thence through another communicating member Ii wherein the same action takes place, to wit: a scraping ci! of the exterior layers while the innermost portion passes freely through the communicating tube. The inner portion of the charge then strikes the diffusing cone i1 which breaks up the same and deflects it towards the inner wall of the shell. Thus it will be seen that by passing the exhaust gases through a plurality of successively arranged tapered tubes that the exterior strata is more or less gradually removed, until finally the interior portion of the gas is caused to be deflected towards the shell and then the gases must pass through the apertures I6 in the numerously perforated bame plate I4 into the gas cushion 2| at the rear of the muiiier, on into the re-entrant pipe 23 and thence to the atmosphere through the outlet I. y

Referring now to Figure 4, the invention, in a modified form, is embodied in a muiller made up of a one-piece shell 30 which shell is rolled into shape and formed with a longitudinal welded seam. Within the shell are several transverse plates 3|, each having formed centrally therein a tapering tubular member 33 and which plates f may be welded, as shown 'at 32, to the shell. Figure 6 shows the communicating tube 33 on plate 3i in shell 30 through which the exhaust gases pass and are acted upon in the manner described in connection with Figure 1. The inlet of this muiiler is shown at 35, and the outletat 36. Disposed near the 'inlet there is positioned a baille plate 31 provided with a-plurality of apertures 38, shown in Figure 5. This perforated plate causes an initial diffusing of the exhaust gases, whereupon they pass through several successively arranged tapering tubular openings 33. Immediately to the rear of the last tapering tubular opening there may be placed a plate 39, provided with a plurality of openings 40, and a conical diffusing cone 42 which aids in diffusing the heart or central portion of the exhaust gases.

In adapting the muilier, shown in Figure 4 to engines of various sizes, types and characteristics, it is contemplated that the number of the tapering tubular members, as well as the transverse baille plates, may be varied and the diffusing cone as shown may, or may not, be used. Further, it is contemplated that the arrangement of baille members shown herein may by modifications that are obvious, be embodied and used in either sec tional or shell type muiiiers.

, 'I'he operation of this invention having been hereinbefore explained, illustrated and described, with a considerable degree of particularity as to theconstructional details of the devices shown herein, it is to be understood that the invention is not limited to these forms and arrangements of the several parts which may be modified within a wide range without departing from the essence of the present invention, and, therefore only such limitations are to be placed thereupon as are imposed by the prior art or as specifically set forth in the sub-joined claims. The present construction and the description based thereupon is intended to be taken in a descriptive rather than a limiting sense.

Having thus described the invention and desiring to secure and protect the same by Letters Patent of therUnited States, I claim:

l. In an exhaust gas muiller the combination of a shell, heads at the opposite ends having respectively an inlet and an outlet, transversely extending flat partition plates in said shell spaced from the heads and from each other and forming a plurality of chambers, each of the said plates having an aperture approximately half the diameter of the shell, a longitudinally extending tubular member secured to each aforesaid plate within said aperture and tapering to be smaller at its end towards the outlet and a further baille plate numerously perforated over its area and placed across the shell, and spaced from the nearest tubular member and from either head.

2. In a muiiler having an inlet at one end and an exhaust at the other., a mummy of chambers for the progression of exhaust gases and megaphoneshaped members permitting communication between said chambers, whereby to permit the progression of said gases through said chambers, partitions having perforations for breaking up and segregating the exhaust gases and a pipe extending into said muiller at the exhaust end to forma gas cushion in said muiiier to aid in deadf ening the sound of the exhaust gases before they reach the atmosphere. A

3. In a muiiler, having an inlet at one end and an exhaust at the other, a plurality of cups formvsaid gases through said chambers, partitions having perfor-ations for breaking up and segregating the exhaust gases and a pipe projecting into certain of said chambers at the exhaust end whereby Vto form a pocket adapted to aid in deadening the sound of the exhaust gases before they reach the atmosphere.

4. In an exhaust gas mumer the combination of ashell, heads at the opposite ends having respectively an inlet and an outlet, transversely extending iiat partition plates in said shell spaced from the heads and from each other and forming a. plurality of chambers, each of the said plates having an aperture of a substantial area, a longitudinally extending tubular member'secured to each aforesaid plate within said aperture and tapering to be smaller at its free end pointed towards the outlet, a further bame plate numerously perforated over its area placed across the shell, spaced from the nearest tubular member and either head, and a pipe extending into said muilier at the exhaust end and secured thereto. AMBROSE J. MCNAMARA. 

